Uncorrected blood sample variances plotted as a function of dose. Preirradiated s²₁, ○; 70-day postirradiation s²₂, ▴; and 130-day postirradiation s²₂, ▪. Fitted curve, —, described by equation 4, where average s²₁ = 0.0097, D₀ = 0.82 Gy, and N = 8,700 cells. Keeping D₀ and s²₁ constant, but varying N between 5,000 and 25,000 cells, generates upper and lower limits, - - - - , encompassing all variances measured postirradiation for doses greater than 4.0 Gy.